The present invention relates to the monolithic integration of epitaxial device layers with CMOS devices. The present disclosure is based on prior art described in U.S. Pat. No. 6,943,051; and co-pending patent application Ser. No. 11/176,538.
Said prior art provides a method of fabrication, and several variations of same, that enable the integration of CMOS devices and epitaxial layer devices, such as photo-diodes, avalanche photo-diodes, stacked multi-layer photo-diodes, heterojunction bipolar junction devices, IMPATT devices, etc.
The present disclosure provides more variations to said method of fabrication, with the goal of providing improving the manufacturability and performance of the fabricated devices.
For example, there are new embodiments depicting certain doping configurations, by ion implantation, of the substrate underneath the epitaxial layers and possible combinations of said doping configurations with the layout of the hard mask for epitaxy. There are also embodiments for the integration of epitaxial layer devices formed in the inner region of Ring-MOSFETs.
The present disclosure provides specific embodiments for the integration of the epitaxial layer devices with MOSFETs (rectangular-gate of ring-gate), made on the same active area.